With the advancement of high volume manufacturing of relatively thin, pliable materials, die cutting machines employing cylindrically-shaped rotary cutting dies have gained increased usage. Rotary die modules or frames which support and retain the cutting die rolls in operation typically consist of thick, rigid, machined steel bases, top plates and sidewalls. The sidewalls typically require a U-shaped vertical slot opening to the top of the sidewall and frame which are closed when the top plates are secured to the sidewalls. The sidewalls and slots are required to be machined to close tolerances to precisely locate bearing blocks on each end of the rolls to properly align and maintain position of the cutting rolls related to one another both in rotation and in linear movement along their axes of rotation. Prior design frames are typically welded or securely bolted together requiring significant time and effort to disassemble them to change or service the dies or frame.
Other known devices have improved upon modules requiring two bearing blocks per roll, but still rely on heavy machined steel frames and bearing blocks on at least one end of the die roll to support and control rotation of the dies relative to the frame and one another. Prior art modules are limited in their flexibility of adapting to different die rolls, die diameters and applications such as high versus low speed operations. The lack of adaptability stems from machined steel frames, integration of the die supports with the frame, and reliance on bearing blocks to support and retain the die rolls in operation.
To install or change the die rolls in the known die modules described above, the top plate is typically removed and each die with attached bearing blocks is loaded into the frame from the top with an overhead lifting device or hoist. The bearing blocks are precisely positioned in the unshaped slots in the sidewalls. Precision spacer blocks are used to vertically position the bearing blocks and thus, the dies in the sidewalls of the frame. A set of spacers is typically placed in the slots on top of the lower die roll bearing block to separate the lower roll from the upper die roll. The spacers require precise machining to properly space the cutting blades on the die rolls from one another. Once the die rolls are positioned, the top plate is secured to the sidewalls and pressure screws compress the stack of spacers and bearing blocks to prevent movement. The die rolls are supported by the frame and rotate about the bearing blocks attached to the dies.
If a die roll needed to be removed, the top plate and the stack of bearing blocks and spacers would need to be removed from the top of the frame by an overhead hoist and the new die installed. This would require completely readjusting the stack using different or additional spacers to compensate for the new die or dies. Other prior design frames permit cutting sleeves to be axially removed through a side of the frame leaving the arbors rigidly positioned in the frame, the arbors, like prior design rolls, are removed from the top of the module.
These removal, installation, and adjustment processes are time consuming resulting in significant down time of the die module. Due to the costly steel frames and associated die rolls, it is cost prohibitive to have extra frames with installed alternate dies to reduce changing and readjusting the modules. Further, prior frames were dedicated to using a particular type of die roll and bearings to support and retain the rolls.
Due to the nature of the prior designs, prior frames were complex in design, expensive to manufacture and assemble and required extensive time to change and readjust the die rolls.
Consequently, it would be desirable to provide a die module improving the problematic conditions in prior rotary die module designs and to provide a module that is inexpensive, facilitates manufacturing, assembling and service, and effectively maintains high precision and quality-cut materials. It would also be desirable to provide a module that is inexpensive to the point that additional frames could be purchased for each die set eliminating the need and associated expenses in changing and adjusting die rolls in a particular frame. It would also be desirable to provide a method of installing and removing dies from a single die frame which was simple and efficient to carry out. It would also be desirable to provide a die module that is relatively easy to move and transport to facilitate flexibility in the placement and integration of the die module in a manufacturing facility.